This circuit was found in the May 1990 Radio Electronics magazine. The timings depend on the capacitors and the supply voltage depends on the relay used.
Found in a magazine 73 for radio amateurs, this circuit makes use of general purpose transistors and...
We found this circuit very simple in an old documentation. The relay is high voltage sensitive, but...
This ultra-simple 9 V power source was obtained in an Argentine publication of the 1970s, but it...